The effect of Cr impurity to superconductivity in electron-doped BaFe2-xNixAs2

TL;DR

This study investigates how Cr impurity affects superconductivity in electron-doped BaFe2-xNixAs2, revealing impurity suppression of superconductivity and restoration of antiferromagnetic order, with detailed phase diagram analysis.

Contribution

It provides the first detailed phase diagram of Cr-doped BaFe2-xNixAs2, showing impurity effects suppress superconductivity and restore magnetic order.

Findings

Cr doping suppresses superconductivity via impurity effects.

Cr doping restores long-range antiferromagnetic order.

Normal state resistivity above 100 K remains unaffected.

Abstract

We use transport and magnetization measurements to study the effect of Cr-doping to the phase diagram of the electron-doped superconducting BaFe2-xNixAs2 iron pnictides. In principle, adding Cr to electron-doped BaFe2-xNixAs2 should be equivalent to the effect of hole-doping. However, we find that Cr doping suppresses superconductivity via impurity effect, while not affecting the normal state resistivity above 100 K. We establish the phase diagram of Cr-doped BaFe2-x-yNixCryAs2 iron pnictides, and demonstrate that Cr-doping near optimal superconductivity restore the long-range antiferromagnetic order suppressed by superconductivity.